Part 19

An olive-brown or smoky brown capped agaric with only slightly swollen stem-base, white patches of volva on the cap and white concentrically scaly stem with unchanging flesh.

Spores: ellipsoid and measuring 8-12 × 7 µm.

~A. phalloides~ (Fries) Secretan

Cap: width 70-85 mm. Stem: width 12-20 mm; length 85-120 mm.

A greenish or yellow-olive capped agaric with stem sheathed in membranous volva, white patches of volva on cap and smooth, white stem with white flesh.

Spores: broadly ellipsoid and measuring 10-12 × 7 µm.

(ii) Lacking ring on stem:--

~A. fulva~ Secretan

Cap: width 40-60 mm. Stem: width 10-15 mm; length 100-150 mm.

A thin, tawny-brown agaric with stem sheathed in membranous volva and pale tawny, slightly scaly stem.

Spores: globose and 10-12 µm in diameter.

~A. vaginata~ (Fries) Vittadini

Differs from A. fulva in the cap being metallic grey or silvery in colour.

(b) Parasites

~Armillaria mellea~ (Fries) Kummer

Honey-fungus

Cap: width 50-150 mm. Stem: width 10-12 mm; length 75-150 mm.

Description: Plate 10.

Cap: at first convex then more or less flattened or slightly depressed, very variable in colour, yellowish, olive, buff, sand-coloured or some shade of brown, at first covered in small, brownish or ochraceous scales which give the young cap a velvety aspect, but gradually the scales disappear with age except at the cap-centre; margin striate and usually paler than centre of the cap.

Stem: equal or swollen at base, often several grouped together, white at apex above a whitish, rather thick, ring which is flushed with olive-yellow or red-brown at its margin; stem-base fibrillose, whitish but finally red-brown at maturity.

Gills: adnate or slightly decurrent, whitish then flushed flesh colour and developing brownish spots with age or in cold, wet weather.

Flesh: with rather strong and unpleasant smell, white or flushed pinkish in the cap, brown and stringy in the stem.

Spore-print: very pale cream colour.

Spores: medium-sized, hyaline, ellipsoid, less than 10 µm in length (8-9 × 5-6 µm).

Marginal cystidia: variable, hyaline, cylindric and not well-differentiated.

Facial cystidia: absent.

Habitat & Distribution: This fungus grows in troops or is found joined at the base to form clusters. It is always attached to old trees, trunks, stumps and buried wood, either directly or by its vegetative stage which darkens and aggregates to form strands resembling boot-laces which are called rhizomorphs.

General Information: This rather variable, and therefore often perplexing, fungus causes a destructive rot of trees and can travel long distances through the soil with the use of its rhizomorphs. It commonly grows on several species of broad-leaved trees, but can also colonise conifer trees. It also attacks garden shrubs, such as privet-hedges, and is particularly destructive to Rhododendrons causing a wilt of the whole shrub and subsequent death; it has also been recorded as attacking potatoes. The actively growing mycelium which can often be found growing under the bark of infected trees, exhibits a luminosity if freshly exposed and placed in a darkened room. The rhizomorphs of A. mellea are highly specialised structures composed of mycelial threads some of which have become rather more differentiated than is normally found in the vegetative stage of other agarics.